Steam turbine system



April 17, 1934,

4 C. E. LUCKE STEAM TURBINE SYSTEM Filed April 12, 1928 Ill W ATTORNEY) Patented Apr. 17, 1934 PATENT OFFICE 1,954,823 STEAM 'ruanmn srs'mrr Charles E. Lucke, New York, N. Y.,

The Babcock &

assignor. to

Wilcox Company, Bayonne,

N, J., a corporation of New Jersey Application April 12, 1928, Serial No. 269,433

10 Claims.

This invention relates to a process whereby the quality of steam passing through the turbine can be so controlled that dry saturated steam can be maintained at the low pressure end of the turbine or as near thereto as is desired. For this purpose, the exhaust steam from a stage of the turbine is reheated in two steps by live superheated steam before it-enters a low pressure stage of the turbine and the amount of thereheating is controlled so that the low pressure steam has the proper amount of superheat when it enters the low pressure stage so that the quality of steam leaving the turbine or approaching the condenser will have the right quality regardless of changes in the load.

The invention will be understood from the description in connection with the accompanying drawing in which Fig. 1 shows somewhat diagrammatically an arrangement of apparatus for carrying out the process. In the drawing reference character 1 indicates a steam pipe from any appropriate source of superheated steam.

. The invention is illustrated in connection with two turbines, one 01 which is a high pressure turbine and the other a low pressure turbine, but

it is to be understood that the invention is also ap-- plicable to a single turbine with high pressure and low pressure stages. The superheated steam from the steam pipe 1 enters the high pressure steam 3o turbine 2, the amount thereof being controlled by the valve 3 and other valves to be described in accordance with the loadon theturbine. An

exhaust pipe i'from the turbine 2 leads to a reheater 5 from which a pipe 6 leads to a second reheater 7, both of these reheaters being heated by live superheated steam. A pipe 8 leads 'from the reheater '7 to the low-pressure turbine 9.

A bypass pipe 10 leads from the pipel in front of the valve 3 to the reheater 7, this pipe 10 being provided with a valve vl1. The reheater 7 may be of any of the well known types in which heat is transferred from one fluid to another without permitting the fluids to come into contact with each other. The reheater? is illustrated as having a lower header 12 to which the pipe 10 leads with tubes 13 extending from the header 1?. to an upper header 14 from which a pipe 15 pro- .vided with a valve 16 leads back to the pipe 1 on the other side of the valve 3. The exhaust steam from the turbine 2 "passing through the reheater 7 is heated by passing alongthe outside ofthe tubes 13 and headers 12 and 14 through which all of the live superheated steam for the turbine 2 or'a definite fraction thereof passes. A branch pipe I'Tprovided with a valve 18 leads (Cl. -73) from the pipe 1 to the reheater 5. This reheater is provided with circular rows of tubes 20 having closed ends so that the reheating steam that enters the same may lose its superheat and then be condensed and the condensate withdrawn. The 60 steam from the pipe 17 enters the circular headers 19 at the upper end and then passes into the rows of tubes 20 that enter lower headers 22 and a drain pipe 23 to remove the condensate-is connected to-the lower headers 22.

'The reheater 5 is such that the increasein the temperature of the exhaust steam from the turbine 2 passing through it around the tubes'20 and headers 19 and 22 is practically constant r'e-' gardless of the amount of this exhaust steam for a constant live steam temperature. The low pressure steam leaving the reheater 5 .is superheated to a temperature lower than the tempera-- ture of the live steam that enters from the pipe 17. Due to the fact that the high pressure tubes of the reheaterb are tubes with dead ends, only so much heat of superheat is supplied to the low pressure steam as corresponds to the weight of the high pressure steam that is actually con-' densed. There is much more steam to be superheated than is condensed in the reheater 5. In order to obtain a still higher temperature in this low pressure steam after it leaves the high pressure turbine,- 'it is passed .through another reheater that is heated by all or a definite fraction of the live steam going to the high pressure turbine.

' The reheater 7 is such that all of the steam on the way to the turbine 2 or a definite fraction thereof is caused to pass through the reheater '7.

The result is that the amount of heat given up to the steam to be heated that passes through the reheater 'l is proportional to the amount of this steam going tov the turbine. By observing the quality-of the steam at the exhaust of the turbine 9 or at a place near its low pressure end, the operator can manipulatethe valves 3.11 and 16 in such a way that the point in the turbine 9 at which the steam becomes saturated can be regulated.

I I claim:

1. In an elastic fluid power plant, the combinae tion of a source of superheated elastic motive fluid, a prime mover comprising a high pressure portion anda low pressure portion, a con- 105 duit providing communication between said source and the inlet of the high pressure portion of the prime mover, a valve in said conduit, means for reheating the motive fluid flowing from the high pressure portion of the prime mover to the 110 1o fluid to the latter, a third conduit communicating with the discharge end of said heating unit and the first conduit intermediate the valve therein and the inlet of the prime mover for returning motive fluid flowing through said heating unit to the motive fluid supply of the prime mover, the heating unit of the lower temperature reheater stage communicating with the heating unit of the higher temperature reheater stage and receiving fluid discharged therefrom, the fluid flowing to the hea g unit of the lower temperature reheater stage being condensed therein.

2. In an elastic fluid power plant, the combination of a source of superheated elastic motive fluid, a prime mover comprising a high pressure portion and a low pressure portion,-a conduit providing communication between said source and the inlet of the high pressure portion of the prime mover, a valve in said conduit, means for reheating the motive fluid flowing from the high pressure portion of the prime mover to the low pressure portion comprising a lower temperature reheater having a heating unit and a higher temperature reheater having a heating unit with said motive fluid flowing successively through the heating units reversely to the order in which they are specified, a second conduit communicating with the first conduit intermediate said source of motive fluid and said valve and with the heating unit of the higher temperature reheater for supplying superheated motive fluid to the latter, a third conduit communicating with the discharge end of said higher temperature reheater heating unit and the first conduit intermediate the valve therein and the inlet of the prime mover for returning motive fluid flowsupply of the prime mover, the heating unit of the lower temperature reheater comunicating with the motive fluid flowing to the prime mover, the fluid flowing through the heating unit of the lower temperature reheater being condensed therein.

3. In an elastic fluid power plant, the combination of a source of superheated elastic motive fluid, a prime mover comprising a high pressure portion. and a low pressure portion, a conduit providing communication between said source and the inlet of the high pressure portion of the prime mover, a valve in said conduit, means for reheating the motive fluid flowing from the high pressure portion of the prime mover to the low pressure portion comprising a lower temperature reheater having a heating unit and a. higher temperature reheater having a heating unit with the motive fluid flowing successively through the reheaters, a second conduit communicating with the first'conduit intermediate said source of inc-- tive fluid and said valve and with the'heating' unit of the higher temperature reheater for supplying superheated motive fluid to the latter, a third conduit communicating with the discharge end of said heating unit and the first conduit intermediate the valve therein and the inlet of the prime mover for returning motive .fluid flowing through said heating unit to the motive fluid ing through said heating unit to the motive fluid supply of the prime mover, and a fourth conduit leading from the first conduit to the heating unit of the low temperature reheater, the fluid flowing to the heating unit of the low temperature reheater being condensed therein.

4. In a power system, a high pressure steam turbine, a low pressure steam turbine, a source of superheated steam, a dead end reheater, a

thorofare reheater, an exhaust pipe leading from the discharge end of the high pressure turbine to the dead end reheater, connections whereby steam heated in the dead end reheater is then conducted to the thorofare reheater whence it passes to the low pressure turbine, means for conducting superheated steam from said source through the thorofare reheater to the inlet of the high pressure turbine, and a connection whereby at least apart of the steam from said source moves directly to the dead end reheater without passing through the thorofare reheater.

5. In a power system of the class described, a high pressure turbine, a low pressure turbine, a dead end-reheater, a thorofare reheater, means connecting the reheaters between the turbines in series in the order named, a source of superheated steam; a conduit leading steam from the source, a second conduit leading from the first conduit to the inlet of the high pressure turbine and including connections whereby steam conducted therethrough is passed to the thorofare reheater as its heating steam, a third conduit by-passing the thorofare reheater so that superheated steam from said source is passed to the dead end reheater to be used as its heating medium without passing through the thorofare reheater, and

means conducting the exhaust steam from the high pressure turbine through the dead end reheater and the thorofare reheater on its way to the low pressure turbine.

6. In a steam turbine power generation system having a plurality of difierent pressure turbine stages, a dead end reheater receiving exhaust steam from the high pressure turbine stage, a thorofare reheater, connections conducting steam heated bythe dead end reheater to the thorofare reheater where its temperature is raised before it ispassed to the low pressure turbine stage, a source of superheated steam, 'a conduit conducting superheated steam from said source, and connectionswhereby steam from the conduit is led-oh" to the thorofare reheater and to the dead end reheater to act as the heating agent therein, some of the steam passing through the conduit and aconnection to the dead end reheater without passing through the thorofare reheater.

7. In a multi-pressure steam turbine power system, a source of superheated steam, a conduit conducting steam from said source to the high pressure turbine stage of the system, a non-condensing reheater, connections between the conduit and the-reheater whereby a part of the conducted steam'is by-passed from the conduit to the reheater and back to the conduit after it has acted as the heating medium in the reheater, a dead end condensing reheater directly receiving and heating the exhaust steam from the high pres sure turbine stage, a connection between the conduit and the dead end reheater whereby a part of the steam in the conduit is led off to act as a heating agent, and means conducting the heated exhaust steam from the dead end reheater through the non-condensing reheater to the low pressure turbine stage.

8. In 'a multiple stage steam turbine system having a steam heated interstage steam reheater;

means for regulating thequality of the steam delivered to the low pressure turbine independently of the quality of the steam received from the high pressure turbine; said means comprising two tu- 5 bular heaters in series with reference to the flow of low pressure steam, connections supplying the first reheater with steam at the pressure and. quality of that entering the high pressure turbine in quantities limited by that which the low pressure steam can condense, a second set of connections supplying the second reheater with a part only of the steam proceeding to the high pressure turbine, the latter steam being caused to flow through the second heater, and means by- ,5 passing the second heater to cause some steam to proceed directly to the first heater without passing through the second. v 9. In a multiple stage: steam turbine system having a steam heated interstage steam reheater; means for regulating the quality of the-steam delivered to the low pressure turbine stage independently of the quality of the steam received from the high pressure turbine stage; said means comprising two tubular heaters in series with reference to the flow of low pressure steam, connections supplying the first reheater with steam at the pressure and quality of that entering the high pressure. turbine in quantities limited by that which the low pressure steam can condense, a second set of connections supplying the second reheater with a regulated fraction only of the j steam on its way to the high pressure turbine stage, the latter steam being caused to flow through the second heater, means for varying or second reheater on its way to the high pressure turbine, and a conduit by-passing the second reheater to permit a part of the steam proceeding to the high pressure turbine stage to pass to the first reheater without having acted as the heating agent of the second reheater.

10. In a steam power system of the type having a sourceof high pressure steam, a high pressure turbine stage, a low pressure turbine stage, a receiver for the steam exhausting from the low pressure stage, a. low temperature reheater, a steamline supplying superheated steam to the high pressure turbine stage, an exhaust steam line conducting the exhaust steam ofthe high pressureturbine stage through the reheater to the low pressure stage, and a connection supplying the reheater with steam of the'pressure and quality of the steam entering the high pressure turbine stage; the combination therewith of a tubular reheater connected with thelow tem; perature reheater in series relative to the flow of exhaust steam from the outlet of the high pressure turbine stage to the steam inlet of the low pressure turbine stage, connections between to-the tubular reheater and for controlling the 

